A color filter is a key component of a liquid crystal display (LCD) for being capable of colorization. In methods for preparing the color filter, a pigment-dispersed method is the most commonly-used method. The pigment-dispersed method may include the following basic steps: coating a color photoresist on a base substrate, and solidifying the color photoresist with an ultraviolet irradiation or the like, to form a pigment photoresistance. The color photoresist includes a color dispersion, which mainly includes a colored pigment, a dispersant, a binder resin and a solvent. The colored pigment in the color dispersion may determine the color of the color photoresist finally formed. The stability of the color dispersion is very important. If the stability of the color dispersion used is not good enough, a deposition or even a cohesion of the pigment particles tends to occur in the pigment dispersion, directly resulting in an unsmooth surface of the color filter layer of the color filter, an uneven coating of the color filter layer, which may further lead to undesirable phenomena such as light leakage of the color filter.
Polyhedral Oligomeric Silsesquioxane (POSS) has a formula of (RSiO1.5)n (n is 6, 8, 10 or a larger even number, and R is an organic group), and is one kind of an organosilicon compound having a special polyhedral molecular structure. Polyhedral oligomeric silsesquioxane is an organic-inorganic nano-hybrided material on a molecular level, not only the structure of an inorganic silica skeleton thereof may provide a steric hindrance effect and enhance the heat resistance, but also the peripheral organic group thereof may increase its reactivity with different substrates.
In the prior art, the POSS structure is introduced into the resin generally by a method of directly mixing a chemical having a free POSS nano-structure or a method of copolymerization. A Chinese invention patent 200680042113.1 relates to a method of using a chemical having a POSS nano-structure as a dispersing addictives, a surface modifier and an interface friction modifier, in order to improve property of a polymer itself and a surface thereof. The patent relates to a method of directly mixing the chemical having the free POSS nano-structure, which results in a poor controllability, but if chemical modification is directly implemented to the polymer itself, a chemical or a physical property of the polymer itself may be influenced. A Chinese invention patent 200610137563.0 relates to a photosensitivity resin composition, which includes an acrylic copolymer, and the acrylic copolymer is obtained by copolymerization of the following compounds i) to iv): i) a polyhedral oligomeric silsesquioxane-containing unsaturated compound; ii) an unsaturated carboxylic acid, unsaturated carboxylic anhydride, or a mixture thereof; iii) an epoxy-containing unsaturated compound; and iv) an olefinic unsaturated compound. The photosensitivity resin composition not only has excellent performances such as homogeneity, sensitivity, resolution, heat resistance and transparency after being developed, but also an organic insulating film with a low dielectric constant can be achieved so as to decrease power consumption and reduce crosstalk. However, since the dispersant is prepared using the method of polymerization, controllability of the POSS modification degree in the dispersant is poor, so that a stable pigment solution using the dispersant may have a poor stability and tendency of agglomeration, and finally the performance of the color photoresist may be affected.